Oh look, a ball that your child can run around inside! Just what you were looking for. The fact that the ball floats on water is even more exciting.
It's also good training so that one day your kid can travel to New Zealand to Zorb (which means to roll down a hill in a bubble).
The video suggests that this is a new method of babysitting in China, while the youtube site suggests that with an ever growing population, this is merely a method of child storage.